Vista - Windows update error 80070424

Hi there,

Windows update giving this error:

Code 80070424 Windows update encountered an unknown error

It worked fine before

I am running avast! anti virus on my Dell Studio 1537, Vista Home Premium 64-bit

I have searched a lot for this but was unable to find a solution

Quick help will be appreciated

Thanks

Click Start >> Run >>
Type the follow command in the Open box.
"net.exe stop wuauserv" (w/o quotes)
Press Ok

Repeat the same for the following commands:

regsvr32.exe wuapi.dll
regsvr32.exe wups.dll
regsvr32.exe wuaueng.dll
regsvr32.exe wucltui.dll
regsvr32.exe MSXML3.dll
regsvr32.exe qmgr.dll
regsvr32.exe qmgrprxy.dll
net.exe start wuauserv
But regsvr32.exe wucltui.dll and regsvr32.exe qmgr.dll failed.

Start regedit.exe and locate the key
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Servic es\wuauserv
If you find a DeleteFlag value there, delete the DeleteFlag value

I tried the following steps but still cannot update and same error still coming:
So any more suggestions?

3rd Method
Resetting the entire Windows Update Component manually

Perform the following steps to reset the Windows Update component manually...


Step 1:
Stopping the Background Intelligent Transfer Service and the Automatic Updates service....

Click Start/All Programs/Accessories. Right click 'Command Prompt' and select 'Run As Administrator'. Click 'Continue' on the UAC prompt.
At the command prompt, type the following commands, and then press ENTER after each command:
net stop wuauserv
net stop bits


Step 2:
Renaming the Catroot2 folder...

Type the following commands, and then press Enter after each command.
net stop cryptsvc
ren %systemroot%\System32\Catroot2 oldcatroot2
net start cryptsvc


Step 3:
Renaming the "SoftwareDistribution" folder...

Type the following command, and then press Enter.
ren %systemroot%\SoftwareDistribution SoftwareDistribution.old


Step 4:
Registering the files that are used by Windows Update and Microsoft Update...

At the command prompt, type the following commands, press ENTER after each command, and then click OK every time that you receive a verification message:
regsvr32 wuapi.dll
regsvr32 wuaueng.dll
regsvr32 wucltux.dll
regsvr32 wups2.dll
regsvr32 wups.dll
regsvr32 wuwebv.dll


Step 5:
Starting the Background Intelligent Transfer Service, the Automatic Updates service, and the Event Log service....

At the command prompt, type the following commands, and then press ENTER after each command:
net start bits
net start wuauserv
net start Eventlog
exit

Reboot the computer and try Windows Update again.

I have tried 3rd method as most people on the thread got successful after applying 3rd method:



But still same error appearing



So now what should I try?